Concentration Mass Percent PPM PPB Volume Percent

Concentration of Solutions The concentration of a solution expresses the amount of solute dissolved in a given quantity of solvent or solution A dilute solution contains a relatively small amount of dissolved solute. A concentrated solution contains a relatively large amount of solute.

Concentration - Mass Percent Solution Mass percent expresses the concentration of solution as the mass of solute in a given mass of solution. The mass of solution = mass of solute + mass of solvent

Examples of Mass Percent Problems What is the mass percent of sodium hydroxide in a solution that is made by dissolving 8.00 g NaOH in 50.0 g H2O? What masses of potassium chloride and water are needed to form 250.0 g of 5.0% solution? A 34.0% sulfuric-acid solution has a density of 1.25 g/mL. How many grams of H2SO4 are contained in 1.00 L of this solution?

Concentration – PPM (Parts per Million) ppm expresses the concentration of solution as the mass of solute in a given mass of solution. *The mass of solution = mass of solute + mass of solvent ppm is typically used for very small concentrations

Examples of ppm Problems A 250 .0 mL sample of drinking water is found to contain 0.003 g of lead. What is the concentration in ppm? A 1.0 L air sample contains 4.25 × 10−4 g of CO2. Express the concentration of CO2 in the air in ppm. The density of atmospheric air is 1.29 g/L at the Earth’s surface. A 250.0 mL sample of boiler feed water has a carbonate concentration of 45 ppm. What is the mass of carbonate ion in the sample? The density of the feed water is 999.5 g/L at 22.0°C.

Concentration – PPB (Parts per Billion) ppm expresses the concentration of solution as the mass of solute in a given mass of solution. *The mass of solution = mass of solute + mass of solvent ppb is typically used for very small concentrations

Examples of ppb Problems What is the concentration, in ppb, of PCBs in a chemical spill if there is 0.0060 mg in 4600 kg of soil? What is the mass of nickel, in mg, in 2.4 kg of propanol if the concentration is 20 ppb? What is the concentration, in ppb, if 0.081 g of CaCl2 is dissolved in 1.50 kg of water?

Concentration – Volume Percent This form of concentration can be used for solutions formed from two liquids or two gases Volume percent is the volume of the solute in 100 mL of solution

Volume Percent continued If a bottle of wine is 12% alcohol by volume there are 12 mL of alcohol per 100 mL of wine Note: liquid volumes are not necessarily additive due to intermolecular forces between the molecules of solute and solvent and the shape of the molecules To make a 60% solution of isopropyl alcohol add enough water to 60 mL of the alcohol to bring the total volume of the solution to 100 mL The volume of water added may not be 40 mL

Examples of %v/v Problems Determine the volume percent of the following: 37.5 mL of butanol dissolved in enough ethanol to make a 300 mL solution 6.0 mL of methanol dissolved in enough water to make a 25.0 mL solution 50.0 mL isoamyl alcohol dissolved in enough acetone to make an 800 mL solution